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NEET PHYSICSEasy

A constant torque of 100 N m100\text{ N m} turns a wheel of moment of inertia 300 kg m2300\text{ kg m}^2 about an axis passing through its centre. Starting from rest, its angular velocity after 3 s3\text{ s} is:

A

1 rad/s1\text{ rad/s}

B

5 rad/s5\text{ rad/s}

C

10 rad/s10\text{ rad/s}

D

15 rad/s15\text{ rad/s}

Step-by-Step Solution

Given: Torque τ=100 N m\tau = 100\text{ N m} Moment of inertia I=300 kg m2I = 300\text{ kg m}^2 Initial angular velocity ω0=0\omega_0 = 0 (since it starts from rest) Time t=3 st = 3\text{ s}

From Newton's second law for rotational motion, the angular acceleration α\alpha is given by: τ=Iα    α=τI=100300=13 rad/s2\tau = I\alpha \implies \alpha = \frac{\tau}{I} = \frac{100}{300} = \frac{1}{3}\text{ rad/s}^2

Using the first equation of rotational kinematics, the final angular velocity ω\omega is: ω=ω0+αt\omega = \omega_0 + \alpha t ω=0+(13)×3=1 rad/s\omega = 0 + \left(\frac{1}{3}\right) \times 3 = 1\text{ rad/s}.

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